LT1076-5 Datasheet, PDF (1/4 Pages) Linear Technology – 5V Step-Down Switching Regulator

FEATURES
s _{Fixed 5V Output}
s _{2A On-Board Switch}
s _{100kHz Switching Frequency}
s _{2% Output Voltage Tolerance Over Temperature}
s _{Greatly Improved Dynamic Behavior}
s _{Available in Low Cost 5-Lead Package}
s _{Only 9.5mA Quiescent Current}
s _{Operates Up to 60V Input}
APPLICATI S
s _{5V Output Buck Converter}
s _{Tapped Inductor Buck Converter with 4A Output}
at 5V
s _{Positive-to-Negative Converter}
LT1076-5
5V Step-Down
Switching Regulator
DESCRIPTIO
The LT1076-5 is a 2A fixed 5V output monolithic bipolar
switching regulator which requires only a few external
parts for normal operation. The power switch, all oscillator
and control circuitry, all current limit components, and an
output monitor are included on the chip. The topology is
a classic positive “buck” configuration but several design
innovations allow this device to be used as a positive-to-
negative converter, a negative boost converter, and as a
flyback converter. The switch output is specified to swing
40V below ground, allowing the LT1076-5 to drive a
tapped inductor in the buck mode with output currents up
to 4A.
The LT1076-5 uses a true analog multiplier in the feedback
loop. This makes the device respond nearly instanta-
neously to input voltage fluctuations and makes loop gain
independent of input voltage. As a result, dynamic behav-
ior of the regulator is significantly improved over previous
designs.
On-chip pulse by pulse current limiting makes the LT1076-
5 nearly bust-proof for output overloads or shorts. The
input voltage range as a buck converter is 8V to 60V, but
a self-boot feature allows input voltages as low as 5V in the
inverting and boost configurations.
The LT1076-5 is available in a low cost 5-lead TO-220
package with frequency pre-set at 100kHz and current
limit at 2.6A. See Application Note 44 for design details.
TYPICAL APPLICATI
Basic Positive Buck Converter
8V TO 40V
+
V_IN
V_SW
LT1076-5
GND
C3
200µF
SENSE
V_C
R3
1.5k
C2
0.033µF
100µH**^†
MBR340*
5V
≤1.8A
* MBR330P MAY BE USED
FOR V_IN ≤ 25V
** ^{COILTRONICS #100-1-52}
HURRICANE #HL-AG210LL
+ _C1
500µF
25V
† _{VALUE MAY BE REDUCED TO 50µH}
FOR OUTPUT LOADS BELOW 1.5A
LT1076-5 TA01
1